1. Field of the Invention
The present invention relates to a wired circuit board and, more particularly, to a wired circuit board such as a suspension board with circuit on which an electronic component is mounted.
2. Description of the Related Art
A wired circuit board such as a suspension board with circuit includes, e.g., a metal supporting board made of a stainless steel foil or the like, an insulating base layer made of a polyimide resin or the like and formed on the metal supporting board, a conductive pattern made of a copper foil or the like, having a plurality of wires, and formed on the insulating base layer, and an insulating cover layer made of a polyimide resin or the like and formed on the insulating base layer to cover the conductive pattern. Such a wire circuit board is widely used in the field of various electric and electronic equipment.
To prevent electrostatic breakdown of an electronic component mounted on such a wire circuit board, it has been proposed to form a semiconductive layer by successively laminating a metal thin film and a metal oxide layer on the surfaces of the insulating cover layer and the insulating base layer of a suspension board with circuit and remove the electrostatic charging by means of the semiconductive layer (see, e.g., Japanese Unexamined Patent Publication No. 2004-335700).
It has also been proposed to form a semiconductive layer on the surface of an insulating layer, form through holes extending through the insulating layer and the semiconductive layer to expose a conductive layer, form connection terminals in the through holes to bring the semiconductive layer into contact with the connection terminals to remove the electrostatic charging of the insulating layer and the conductive layer (see, e.g., Japanese Unexamined Patent Publication No. 2003-152383).